System and method for conditioning gas for downhole applications

Abstract

A method for conditioning natural gas for downlink applications comprising pulling raw gas; cooling the gas to a temperature within a preset temperature range; removing solid contaminants and condensed liquids from the gas; reducing gas pressure to meet the requirements of the inlet side of a compressor; controlling the rotational speed of the compressor based on data input from various flow meters; delivering the preconditioned gas to the suction side of the compressor; elevating gas pressure to achieve a desired discharge pressure; using an aerial cooler to cool the pressurized gas; delivering the pressurized gas to a separator to separate the liquids from the gas; repeating the compression, cooling and separating steps until desired temperature and pressure are achieved; cooling the gas through the use of a heat sink; removing liquids from the gas through the use of a separator; and adjusting the final gas pressure and temperature.

We claim: 
     
         1 . A method for conditioning natural gas for downhole applications comprising:
 (a) pulling raw gas from a source;   (b) cooling the raw gas to a temperature within a preset temperature range for an inlet of a compressor;   (c) removing any solid contaminants and condensed liquids from the raw gas to produce preconditioned gas;   (d) determining pressure requirements of a suction side of a compressor;   (e) reducing pressure of the preconditioned gas to meet the requirements of the suction side of the compressor using a first automated pressure regulator;   (f) wherein the compressor has a rotational speed, controlling the rotational speed of the compressor based on data input from a flow meter located downstream of the compressor, a flow meter located upstream of the compressor, and one or more transducers located on the suction side of the compressor;   (g) delivering the preconditioned gas to the suction side of the compressor;   (h) elevating pressure of the preconditioned gas to achieve a desired discharge pressure and generate pressurized gas;   (i) using an aerial cooler to cool the pressurized gas, thereby causing liquids to form;   (j) delivering the pressurized gas to a separator to separate the liquids from the preconditioned gas;   (k) repeating the steps of elevating pressure of the preconditioned gas through a series of compression stages to achieve a desired discharge pressure and generate pressurized gas, using an aerial cooler to cool the preconditioned gas, and delivering the preconditioned gas to a separator to separate liquids from the preconditioned gas until a gas stream having a desired gas temperature and a desired pressure is achieved;   (l) cooling the pressurized gas by using a first temperature sensor to send a signal to the programmable automation controller to maintain a desired temperature set by an operator and generate cooled gas through the use of a heat sink;   (m) removing liquids from the cooled gas through the use of a separator to generate conditioned gas;   (n) wherein the conditioned gas has a pressure, adjusting the pressure of the conditioned gas by using a pressure sensor located in the gas stream to send a gas supply pressure signal to the programmable automation controller and using the programmable automation controller to control a second automated pressure regulator to adjust the pressure of the conditioned gas without affecting the flow rate of the conditioned gas; and   (o) adjusting the temperature of the conditioned gas by using a second temperature sensor situated in the gas stream to send a signal to the programmable automation controller to increase the temperature of the conditioned gas using an automated injection valve situated between the series of compression stages and a heat exchanger to achieve an exit temperature specified by the operator for the conditioned gas.   
     
     
         2 . The method of  claim 1 , further comprising the step of removing water from the pressurized gas through the use of a dehydration method. 
     
     
         3 . A system for conditioning natural gas for downhole applications comprising:
 (a) a programmable automation controller configured to accept operator-input specifications for desired gas outlet pressure, desired gas outlet temperature, and desired gas outlet flow rate and to independently control each of these three parameters;   (b) one or more gas pressure sensors, one or more gas temperature sensors, and one or more gas flow meters configured to transmit data to the programmable automation controller;   (c) a first aerial cooler configured to adjust temperature of pre-conditioned gas;   (d) a first separator configured to remove liquids from the pre-conditioned gas;   (e) a first automated pressure regulator configured to regulate inlet pressure of the pre-conditioned gas;   (f) a compressor having a first stage of compression with a variable volume pocket, the compressor being configured to receive and compress the pre-conditioned gas, thereby increasing pressure and temperature of the pre-conditioned gas to generate pressurized gas;   (g) an external heat sink configured to decrease temperature of the pressurized gas to generate conditioned gas;   (h) a second automated pressure regulator configured to reduce pressure of the conditioned gas to the desired gas outlet pressure; and   (i) a heat exchanger configured to increase temperature of the conditioned gas to the desired gas outlet temperature;   wherein the PAC is further configured to control pressure, rotational speed and pocket size of the compressor to achieve the desired outlet gas flow rate.   
     
     
         4 . The system of  claim 3 , wherein the compressor has one or more compression stages, the invention further comprising an additional aerial cooler and an additional separator for each additional stage of compression beyond the first stage of compression. 
     
     
         5 . The system of  claim 3 , further comprising a gas dehydration unit configured to remove water from the pressurized gas.